Toán Lớp 6: 1+1/2+1/2^2+1/2^4+1/2^6+...+1/2^98+1/2^100 -

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Toán Lớp 6: 1+1/2+1/2^2+1/2^4+1/2^6+…+1/2^98+1/2^100

Uyên Thi Tháng Hai 22, 2023 Toán học 2 Comments 0 views

Toán Lớp 6: 1+1/2+1/2^2+1/2^4+1/2^6+…+1/2^98+1/2^100

Comments ( 2 )

minhhaanh
22 Tháng Hai, 2023 at 3:52 chiều

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Đặt A = 1 + 1/2 + 1/2^2 + 1/2^4 + 1/2^6 + …. + 1/2^98 + 1/2^100

A . 2^2 = 2^2 + 2 + 1 + 1/2^2 + 1/2^4 + …. + 1/2^96 + 1/2^98

A . 4 = 4 + 2 + 1 + 1/2^2 + 1/2^4 + …. + 1/2^96 + 1/2^98

A . 4 – A = ( 4 + 2 + 1 + 1/2^2 + 1/2^4 + …. + 1/2^96 + 1/2^98 ) – ( 1 + 1/2 + 1/2^2 + 1/2^4 + 1/2^6 + …. + 1/2^98 + 1/2^100 )

A . 3 = ( 4 + 2 )- 1/2^100

A . 3 = 6 – 1/2^100

A = ( 6 – 1/2^100 ) : 3

A = ( 6 – 1/2^100 )/3
haianhtu97
22 Tháng Hai, 2023 at 3:52 chiều

Reply

Giải đáp+Lời giải và giải thích chi tiết:

Đặt \ \ A=1+1/2+1/2^2+1/2^4+1/2^6+…+1/2^98+1/2^100$\\$=>2^2A=2^2+2+1+1/2^2+1/2^4+…+1/2^96+1/2^98$\\$=>2^2A-A=2^2+2-1/2^100$\\$=>3A=2^2+2-1/2^100$\\$=>A=(6-1/2^100)/3

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